This invention relates to wheeled luggage cases and, more particularly, to those luggage cases that have their wheels (usually two) mounted along the broad longitudinal edge at the bottom of the luggage case, and a handle used to steer the case on these wheels mounted on the upper end of the case. Usually this handle is mounted next to the broad edge at the top of the case and on the same broad side of the case as the wheels. More particularly, this invention is related to such wheeled luggage cases having hooks, straps and the like for carrying an auxiliary luggage case.
An example of this prior type of luggage case is shown in U.S. Pat. No. 4,759,431 (a 16 page copy is incorporated by reference) assigned to Samsonite Corporation, assignee of the subject invention. In this patent, such a luggage case is shown with the steering handle, sometimes called the wheel handle, mounted on a stalk or arm. This arm can be extended to a convenient height for the user to wheel the case on the wheels by tipping the case forward onto the wheels. The arm can be lowered into a cavity or receiver mounted on one face or wall of the luggage case for convenient storage or shipping. This type of luggage case is remarkably stable because the lever arm provided by the wheel handle helps steady the case. Leverage is especially desirable when the case carries other auxiliary cases by using the strap normally stored in the wheel handle.
As discussed in great detail in the above-mentioned U.S. patent, such luggage cases can carry a remarkable amount of luggage and move this luggage along a horizontal surface. When extended the handle arm ideally should position the handle at a comfortable distance above the floor for the user when the case is tipped forward. We have found that the angle to which this case is tipped at an angle to the horizontal depends on how heavily the luggage case is loaded and on whether that luggage case is carrying heavily loaded auxiliary cases. At an ideal angle, the case and handle system will balance on the wheels with only minor vertical support provided at the wheel handle by the user
So, the hand grip height (that distance from the floor to the handle grip when in the wheeling position) should be such that the case almost balances on the wheels while it is being towed, with the user providing a small amount of upward force during the pulling. This would place the ideal angle for towing at about five degrees below the point where the case (or the case and the auxiliary cases attached thereto) is perfectly balanced. This ideal balancing angle (or five degrees below the balancing angle for reasonably comfortable towing) decreases as the load provided by the auxiliary case increases. Because of this, the handle height from the floor becomes a function of the luggage carried and less a function of the comfortable height for the user. The worst case would be to have the tallest person (with a comfortable hand grip height greatest from the floor) towing the heaviest load, that is, a heavily loaded main packing case with heavily loaded auxiliary cases attached. The prior art systems demand that, in this situation, this tall user would lower his or her hand to an unnatural and uncomfortable position to maintain the heavily loaded and burdened luggage case in a more or less balanced position.
An opposite phenomenon exists when a relatively short user (who would presumably have the shortest comfortable hand grip height) is towing a heavily loaded main case, but no auxiliary cases. Thus, there would not be a mass of weight positioned on the trailing side of the wheels to counterbalance the weight of the main packing case. While the user could maintain a towing balance, the user would tend to become more fatigued because a greater net amount of weight is being carried by the user via the wheel handle.
Also, in most prior art wheel handle systems, the height to which the handle can extend is usually limited to the vertical dimension of a wall of the luggage case into which the wheel handle and handle grip can be stored. Generally, one would like to have as long a wheel handle as reasonably possible. A long wheel handle, all other things being equal, provides the greatest leverage for supporting and balancing a luggage load. Also, a long arm helps distance the wheeled case from the user's feet so that the user may stride vigorously without hitting the towed case with the user's heels. One solution to this problem is to construct the wheel handle arm of two or more telescoping sections to reduce its stored height. Another solution is to make the vertical dimension of the luggage case, and thus the vertical dimension of the wall storing the wheel handle arm, much greater than that of a typical luggage case.